I generally use slow drying epoxy to attach scales to my full tang handles but am teaching a class in the next couple of months and, due to the schedule, we do not have the time to let the knives sit overnight before shaping the handles. I can only let them sit for a maximum of 1 hour. It seems that Loctite 324 with the activator is my best bet. Since I've never used it before, Id like to get some strategy advice from those with experience with the product. Im thinking the best way to go about attaching the handle would be to apply the 324 adhesive to each scale, then slide the brass pins through the metal and set each scale on the pins but leaving a gap between the metal and wood. Then spray the activator through the gap on each side and quickly clamp it all together. This way there would be no fumbling with the pins, worry about getting them set and clamped before its too late. Does this sound like a good strategy for those who have used the loctite adhesive? If not, what would you recommend? Also, will the activator negatively affect the outside of the wood in any way? Using this method would obviously get a bit of the activator on the outside of the scales. Hopefully it sands off and doesn't discolor the wood below the surface. Any helpful advice would be much appreciated!
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Method for applying Loctite 324 and activator
- Thread starter Michos
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You’re going to need to use the LOCTITE Primer 7075 with the Speedbonder 324. I’m not sure about the activator. I’ve never used it. To be honest, I haven’t used the 324 much either. I hear great things though. You can find info about the primer here:
http://www.na.henkel-adhesives.com/...6465&msdsLanguage=EN_US&selectedTab=technical
http://www.na.henkel-adhesives.com/...6465&msdsLanguage=EN_US&selectedTab=technical
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I've used 324 a lot. using 326 now, can't tell any diff. Put the primer on the tang & the glue on the handle material (very thin coat). Have found the handle material will soak up the primer too much and not activate the glue. Put the pins through one scale and slide in onto to tang, then quickly slide the other scale on and clamp. Dry fit first and make sure it goes together very easily. This stuff is the best glue I've used, but you have to be quick. 3-5 minutes and you're good to go.
Thank you for the tips Don. After chatting with a loctite rep, I decided to buy the brush on primer instead of the aerosol which sounds consistent with your method. I just got a 50ml bottle of 324 in the mail and notice that its only 1/3 of the way full. I assume that it is supposed to come this way and I didn't get scammed... right??
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You didn't get screwed on your bottle of 7075 liquid, except by Loctite, that's how it comes, unfortunately.
I've been using the 7649 primer in an aerosol instead. It's compatible with all the Speedbonder 3xx adhesives. My understanding, according to manufacturer's literature, is that you want to apply the primer, and let it dry first, before gluing. The 7649 primer can be applied up to like 30 days in advance supposedly, so you can actually get everything prepped ahead of time, and then glue when you're ready.
Unlike Epoxy, especially with the 1 min fixture time variety, you don't want to apply the glue and then "spread" it out into a thin layer. I personally just apply a line all around the profile of the handle area, around the pin holes, and if it's a big area, some in the middle, but a little goes a LONG way, much less than you think I'd say. With the 60 second stuff, when I tried to "spread" it, it would actually start setting up where I used a popsicle stick trying to spread.
Just put it on the tang/liners/whatever, align the scales or whatever, and clamp it. The glues are anaerobic, meaning, they start curing in the absence of air, i.e. as soon as you start clamping. With the 5 min version, you've got time to adjust, but with the 60 second stuff, you better have it all where you want it, or you're gonna be beating it apart. The advantage to being anaerobic however, is that whatever "squirts" out when you clamp it, doesn't cure hard, as long as you don't have anything touching it. You can wipe it off with q-tips, or once it dries tacky, pull it off with your fingernail, without messing up finishes. Epoxy on the other hand, you're screwed. It's why I stopped using Acraglas. I'd clean clean clean, then come back an hour later and find fresh glue worked it's way out. No matter how much I cleaned it, I'd come back the next day and have some glue hard cured on the outside that would be impossible to remove without collateral damage.
I've found the 60 second stuff actually harder to disassemble than the 5 min variety personally. It's so heat tolerant, that I usually ruin the handle material trying to heat it off, it usually is smoking or burning before the glue will release, and almost anything will warp under those circumstances. It's good stuff.
Now, prep is key, if you don't have primer or the smallest amount of oil on some section of a tang, it wont stick, but you'll still play hell getting it off where it did.
I've been using the 7649 primer in an aerosol instead. It's compatible with all the Speedbonder 3xx adhesives. My understanding, according to manufacturer's literature, is that you want to apply the primer, and let it dry first, before gluing. The 7649 primer can be applied up to like 30 days in advance supposedly, so you can actually get everything prepped ahead of time, and then glue when you're ready.
Unlike Epoxy, especially with the 1 min fixture time variety, you don't want to apply the glue and then "spread" it out into a thin layer. I personally just apply a line all around the profile of the handle area, around the pin holes, and if it's a big area, some in the middle, but a little goes a LONG way, much less than you think I'd say. With the 60 second stuff, when I tried to "spread" it, it would actually start setting up where I used a popsicle stick trying to spread.
Just put it on the tang/liners/whatever, align the scales or whatever, and clamp it. The glues are anaerobic, meaning, they start curing in the absence of air, i.e. as soon as you start clamping. With the 5 min version, you've got time to adjust, but with the 60 second stuff, you better have it all where you want it, or you're gonna be beating it apart. The advantage to being anaerobic however, is that whatever "squirts" out when you clamp it, doesn't cure hard, as long as you don't have anything touching it. You can wipe it off with q-tips, or once it dries tacky, pull it off with your fingernail, without messing up finishes. Epoxy on the other hand, you're screwed. It's why I stopped using Acraglas. I'd clean clean clean, then come back an hour later and find fresh glue worked it's way out. No matter how much I cleaned it, I'd come back the next day and have some glue hard cured on the outside that would be impossible to remove without collateral damage.
I've found the 60 second stuff actually harder to disassemble than the 5 min variety personally. It's so heat tolerant, that I usually ruin the handle material trying to heat it off, it usually is smoking or burning before the glue will release, and almost anything will warp under those circumstances. It's good stuff.
Now, prep is key, if you don't have primer or the smallest amount of oil on some section of a tang, it wont stick, but you'll still play hell getting it off where it did.
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this stuff is expensive so I stock up when I see deals on eBay, all my bottles are also only partially full, I suspect this has something to do with the anaerobic function, so there is enough air in the bottle....? idk
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That's the way it comes & it'll likely get too old before you use it all. It does have an expiration date, but I've used it way past the date with no issues. It gets thicker with age, but still works. I also use the brush on primer.
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Good info Javan, but except; I prefer a very thin even coat on the scales & have never had it start to set up until it comes in contact with tang of liner. I only apply primer to the opposite part, usually tang or liners. The thinner I spread it out the stronger the bond.
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Interesting Don. I've only had that happen with the 60 second stuff fwiw, although I can't recall if I had primer on both sides or not. Maybe so, I'll have to experiment with it some more.
I will add though, that, in this case, the primer/activators, are *not* necessary to make this glue work, it's not a 2 part system like epoxy. It's more accurate to call them "accelerators" like the stuff you use with CA glue (this is an acrylic adhesive also), they just make the glue set in the advertised working times.
I usually just heat the bottle up a bit by placing it on a light, put as super thin line, and clamp hard, letting the excess squirt out. I haven't had any issues with a gap or too much glue on the ones I've had to force-ably disassemble because of some alignment issue or other operator error though.
Good to get more info here though, there's definitely some differences with this stuff compared to epoxy and not much information about using it floating around.
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Javan, yeah there's more than one way to use this stuff. I'm only using the 60 second stuff (326). The only time I've had it start setting up too soon, is when I primed both surfaces.
My son Kyle had trouble a while back, then found him applying it way too thick. I apply it so thin there is very little clean up around the edges.
I have the loctite, g-flex and the thickened G-flex version. For doing white oak scales-G10-tang, would you use a different glue for the wood to G10 bond vs the G10 to steel? I did read the old KN thread on adhesives a few months back, there was some dedication to testing.
Just wanted to follow up and thank everyone again. We made 7 knives in my class and the 324 with primer worked perfectly. We cleaned the metal with alcohol, applied the primer to the metal, applied a thin coat of the 324 to the wood, slid the pins through one scale, pushed that through the metal, quickly pushed the second scale on the other side and clamped within a minute or so. The loctite rep told me id have about 5 minutes but I found that once the scales were on, if I had to adjust the pins in one direction or another, I did have to pound them pretty good with a hammer to get them to move, even after 15 seconds. Still, it worked great and we only let them sit for about 20 minutes before shaping the handles. Didn't have any issues at all. Ive always told my students to use high quality slow drying epoxy but I may start using the 324 on my own knives, even if I don't need it to set right away.
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Oil the pins, and you shouldn't have as much trouble moving them. Just a light, finger coating, you dont want any dripping off, as it may contaminate the glue-up area where the pins intersect. You can also use grease or vaseline, just make sure it wont cause problems with the handle material.